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Attack Tree Analysis for miguelpruivo/flutter_file_picker

Objective: Compromise the application by exploiting vulnerabilities related to file handling introduced by or exacerbated by the use of flutter_file_picker, leading to unauthorized access, data manipulation, or disruption of service.

Attack Tree Visualization

Attack Goal: Compromise Application via File Picker **[CRITICAL NODE]**

└───[OR]─> 1. Exploit Malicious File Upload **[CRITICAL NODE]** **[HIGH RISK PATH]**
    │       └───[OR]─> 1.1. Social Engineering to Select Malicious File **[HIGH RISK PATH]**
    │           │       └───[AND]─> 1.1.1.1. Misleading File Extensions/Names **[HIGH RISK PATH]** **[CRITICAL NODE - Implicit]**
    │           │       └───[AND]─> 1.1.2. Exploiting User Ignorance/Lack of Awareness **[HIGH RISK PATH]** **[CRITICAL NODE]**
    │           │               │       └───[Leaf]─> 1.1.2.1. User unaware of file type risks **[HIGH RISK PATH]** **[CRITICAL NODE]**
    │           │               │       └───[Leaf]─> 1.1.2.2. User trusts file source without verification **[HIGH RISK PATH]** **[CRITICAL NODE - Implicit]**
    │       └───[OR]─> 1.2. Exploiting File Processing Vulnerabilities (Backend or Frontend) **[CRITICAL NODE]** **[HIGH RISK PATH]**
    │           │       └───[AND]─> 1.2.1. Path Traversal Vulnerability **[HIGH RISK PATH]**
    │           │               │       └───[Leaf]─> 1.2.1.1. Unsanitized File Paths from File Picker **[HIGH RISK PATH]** **[CRITICAL NODE]**
    │           │       └───[AND]─> 1.2.2. File Type Mismatch/Bypass **[HIGH RISK PATH]** **[CRITICAL NODE]**
    │           │               │       └───[Leaf]─> 1.2.2.1. Application expects specific file type, attacker uploads different type disguised **[HIGH RISK PATH]** **[CRITICAL NODE]**
    │           │               │       └───[Leaf]─> 1.2.2.2. Inadequate File Type Validation (Client-side or Server-side) **[HIGH RISK PATH]** **[CRITICAL NODE]**
    │           │       └───[AND]─> 1.2.3. Vulnerabilities in File Parsing/Processing Libraries **[CRITICAL NODE]**
    │           │               │       └───[Leaf]─> 1.2.3.1. Buffer Overflows in Image/Document Processing **[CRITICAL NODE]**
    │           │               │       └───[Leaf]─> 1.2.3.2. Exploiting Known Vulnerabilities in Libraries used to process picked files **[CRITICAL NODE]**
    │           │       └───[AND]─> 1.2.4. Deserialization Vulnerabilities (if applicable) **[CRITICAL NODE]**
    │           │               │       └───[Leaf]─> 1.2.4.1. Processing serialized data within uploaded files without proper validation **[CRITICAL NODE]**
    │           │       └───[AND]─> 1.2.5. Resource Exhaustion/DoS via Large Files **[HIGH RISK PATH]**
    │           │               │       └───[Leaf]─> 1.2.5.1. Application not handling large files gracefully, leading to crashes or slowdowns **[HIGH RISK PATH]** **[CRITICAL NODE]**
    │
└───[OR]─> 3. Exploit Client-Side Vulnerabilities in File Picker Integration **[HIGH RISK PATH - Implicit, related to file handling bypass]**
    │       └───[AND]─> 3.2. Client-Side Logic Bypass related to File Handling **[HIGH RISK PATH]**
    │           │       └───[Leaf]─> 3.2.1. Circumventing Client-Side File Type Checks (easily bypassed, but still a threat if relied upon solely) **[HIGH RISK PATH]** **[CRITICAL NODE]**

Attack Tree Path: 1.1.1.1. Misleading File Extensions/Names

  • Attack Vector: An attacker crafts a malicious file (e.g., an executable) and renames it to have a seemingly harmless file extension (like .jpg, .txt, .pdf).
  • Explanation: Users, relying on the displayed filename or icon, might be tricked into selecting and uploading this file, believing it to be safe. If the application then processes or executes this file based on the user's action, it can lead to compromise.

Attack Tree Path: 1.1.2.1. User unaware of file type risks

  • Attack Vector: Attackers rely on the user's lack of understanding about the dangers associated with certain file types (e.g., executables, scripts, documents with macros).
  • Explanation: Users might unknowingly upload malicious files because they are not aware that files beyond simple documents or images can pose a threat.

Attack Tree Path: 1.1.2.2. User trusts file source without verification

  • Attack Vector: Attackers exploit the user's tendency to trust file sources without proper verification (e.g., files received from unknown senders, downloaded from untrusted websites).
  • Explanation: Users might upload malicious files simply because they trust the source from which they obtained the file, without considering the actual file content or potential risks.

Attack Tree Path: 1.2.1.1. Unsanitized File Paths from File Picker

  • Attack Vector: The application uses file paths directly obtained from flutter_file_picker without proper sanitization when performing file system operations (e.g., saving the file, accessing it later).
  • Explanation: Attackers can manipulate filenames to include path traversal sequences like ../ or ..\\. If these paths are not sanitized, the application might access or overwrite files outside the intended directory, potentially leading to unauthorized access or system compromise.

Attack Tree Path: 1.2.2.1. Application expects specific file type, attacker uploads different type disguised

  • Attack Vector: The application expects a specific file type (e.g., images only) but the attacker uploads a different file type (e.g., an executable) while trying to disguise it as the expected type (e.g., by changing the file extension).
  • Explanation: If the application's file type validation is weak or relies solely on client-side checks or file extensions, the attacker can bypass these checks. If the backend then processes the unexpected file type in a vulnerable way, it can lead to exploitation.

Attack Tree Path: 1.2.2.2. Inadequate File Type Validation (Client-side or Server-side)

  • Attack Vector: The application's file type validation mechanisms are weak, easily bypassed, or non-existent, either on the client-side or, critically, on the server-side.
  • Explanation: Weak validation allows attackers to upload file types that the application is not designed to handle securely. This can lead to various vulnerabilities depending on how the application processes these unexpected file types. Relying solely on client-side validation is a prime example of inadequate validation.

Attack Tree Path: 1.2.3.1. Buffer Overflows in Image/Document Processing

  • Attack Vector: The application uses libraries to parse or process uploaded files (like images or documents). These libraries might have buffer overflow vulnerabilities. Attackers craft malicious files designed to trigger these overflows when processed.
  • Explanation: Buffer overflows can allow attackers to overwrite memory, potentially leading to code execution or denial of service. If a vulnerable library is used to process user-uploaded files, it becomes a critical attack vector.

Attack Tree Path: 1.2.3.2. Exploiting Known Vulnerabilities in Libraries used to process picked files

  • Attack Vector: Attackers target known, publicly disclosed vulnerabilities in the specific versions of file processing libraries used by the application.
  • Explanation: If the application uses outdated or vulnerable libraries, attackers can leverage readily available exploit code or techniques to compromise the application by uploading files that trigger these known vulnerabilities.

Attack Tree Path: 1.2.4.1. Processing serialized data within uploaded files without proper validation

  • Attack Vector: The application processes serialized data embedded within uploaded files (e.g., configuration files, object streams). It does so without proper validation or sanitization of the serialized data.
  • Explanation: Deserialization vulnerabilities can allow attackers to inject malicious code or commands within the serialized data. When the application deserializes this data, the malicious code gets executed, potentially leading to remote code execution and full system compromise.

Attack Tree Path: 1.2.5.1. Application not handling large files gracefully, leading to crashes or slowdowns

  • Attack Vector: Attackers upload excessively large files to the application.
  • Explanation: If the application is not designed to handle large files efficiently (e.g., lacks file size limits, doesn't use asynchronous processing), processing these large files can exhaust server resources (CPU, memory, disk space), leading to denial of service, application crashes, or significant performance degradation.

Attack Tree Path: 3.2.1. Circumventing Client-Side File Type Checks (easily bypassed, but still a threat if relied upon solely)

  • Attack Vector: Attackers bypass client-side file type checks implemented in the application (often in JavaScript) before file upload.
  • Explanation: Client-side checks are easily bypassed by intercepting and modifying network requests or by disabling JavaScript. If the application relies solely on client-side checks for security, attackers can upload any file type. While client-side bypass itself is not a direct vulnerability, it's a necessary step to exploit backend vulnerabilities related to file processing if client-side checks are the only line of defense.